I don't think that we have to worry too much about this. Cuphead is pretty much entirely gameplay focused, so the really obnoxious individuals who obsess more over characters and story don't have much to cling to. That, and the game's difficulty will likely put off a lot of the little kids and dumb teenagers who contribute to cancerous fanbases. So I feel like the fanbase will ultimately consist mostly of people who just legitimately enjoy the game.

Except that didn't happen, Undertale is still good but people have fucking tunnel vision and only see the minority of the fans that stink.